1. Field of the Invention
The present invention relates to a memory card with a nonvolatile semiconductor memory and, more particularly, to a memory card with a NAND flash memory and a semiconductor device embedded in the memory card.
2. Description of the Related Art
Some of different flash memory cards are so configured that a host manages physical conditions in the memory cards (indicating which logical sector address is included in which physical block address or which block is in erase state). In such a memory card, the host directly controls a flash memory of the memory card. The host assumes a write unit and an erase unit of the flash memory and executes write access and erase access to the flash memory using a given block size as an erase unit.
A memory card has recently been noticed in which a block size of erase unit is larger than before.
Jpn. Pat. Appln. KOKAI Publication No. 2002-133877 discloses a technique capable of varying in erase size to partly erase data from a memory cell and shortening a time period for erasing data from a larger area.
If no measures are taken when a flash memory in a memory card to be accessed varies in write unit and erase unit (e.g., the block size of erase unit becomes large), a host cannot execute access to the memory card.
The above problem can be resolved by embedding a conversion controller in the memory card. If, however, the internal conditions of the flash memory are maintained as the host indicates, data needs rewriting in units of erase on the flash memory each time the host executes write access and erase access to the flash memory. A load on the internal operations for write and erase therefore increases considerably. The above publication involves a similar problem.